Back To The Future

In Back To The Future, Marty McFly travels back in time and almost prevents his parents from falling in love, thereby nearly erasing himself. This is what is known as the "grandfather paradox" — the logical impossibility of a time traveler going back in time to kill his grandfather before his own father is born.

Thing is, we still don't know all that much about how the space-time continuum operates. So, is actual time travel possible? Here are 10 people who may have done it... maybe...